Modern absorbent articles are typically comprised of four basic layers: a topsheet, an absorbent core, an intermediate layer between the topsheet and the absorbent core, and a backsheet opposite the topsheet. Several design criteria affect the choice of materials for these layers. Both nonwovens and apertured films are used as topsheets, each having advantages and disadvantages. Absorbent cores may be made of many different combinations of materials, including pulp and other fibrous materials as well as super absorbent particles or fibers. Backsheets are typically made of films; sometimes breathable materials may be used, but the primary concern is that the backsheet remain impervious to fluid leakage. Intermediate layers are a more recent addition to the absorbent article market.
In the past, absorbent articles may have contained nonwoven materials between the topsheet and the absorbent core to reduce rewet from the absorbent core to the surface. Recently, intermediate layers of three-dimensional formed film have proven exceptionally successful at preventing rewet as well as increasing strikethrough performance and masking performance.